The present invention relates to improvements in plastic reclosable fasteners with sliders particularly suited for thermoplastic bags and the like and particularly to a zipper slider having separator structure that acts on track structure extending along the length and parallel to the rib and groove elements of the zipper and not between the rib and groove elements as with a conventional zipper. The zipper structure is slit or notched locally at the end where the slider goes when the zipper is closed, to allow the rib and groove elements to interlock fully, making a leakproof closure.
Conventional plastic profile zipper bags use a pair of interlocking profile zipper elements but without a slider. It is possible to close the zipper elements completely across the bag thereby producing a leakproof closure for the bag. Profile zippers with sliders are used on plastic bags, brief cases, etc. Examples of such profile zippers with sliders are made by Flexico--France, Henonville, France and Baron Industries, Inc. New York, N.Y. The separator tab or finger on the slider goes between the zipper elements so that the zipper is always held open for at least a small portion of its length. Such a zipper is not leak-proof. Examples of such zippers or plastic reclosable fasteners and sliders are disclosed in U.S. Pat. Nos. 3,426,396, 3,660,875, 3,713,923, 3,790,992 and 3,806,998. A flexible fastener with unidirectional opening with a slider is shown in U.S. Pat. No. 3,347,298.